1. Field of the Invention
The present invention relates to a wheel lathe for forming and cutting new wheels for railway vehicles and the like, or for grinding wheels worn down or deformed by travel; the wheel lathe having a centering device for lifting the wheels and synchronizing the wheelset center with the spindle center.
2. Description of the Related Art
To cut or grind wheels, two wheels that are moved along laid rails and provided to the right and left of a wheel axle are brought in, raised by a lifter device, fixed using a fixing device to a spindle rotatably supported on a spindle platform, and processed, for example. In these cases, however, the wheelset center of the wheels and the spindle center (processing center) are chucked in alignment with the spindle using a jaw, clamped from the left and right (using a headstock, tailstock, and the like), or are otherwise fixed to the spindle.
In the past, centering devices were used in order to raise such wheels using a lifter device and to align the wheelset center and the spindle center. These centering devices were configured so that, for example, a centering part disposed at the topmost point of the wheels is lowered in synchrony with the raising of the wheels at the same time as the wheels are raised from below, the raising of the wheels is stopped at a position in which the centering part comes into contact with the area at the topmost point of the external edge of the wheels, and fine-tuning is performed in correspondence with the size of the outside diameter dimensions of the wheels to automatically align the wheelset center and the spindle center.
Furthermore, conventional centering devices have a configuration in which a spindle is laterally installed so that the spindle center is positioned in the middle between the raising part of the lifter device and the topmost-point centering part. The lifter device is constructed of two bearing rollers, which are raising parts, and a bearing roller hoisting device for hoisting the rollers; and has a configuration in which the topmost-point centering part is lowered in synchrony with the two bearing rollers and at the same speed as the raising speed when the two bearing rollers are brought into contact with the lower part of the wheels and raised. The spindle center is constantly kept at an intermediate point between the two rollers, and stopping the raising of the wheels when the centering part is brought into contact with the raised wheels therefore allows the wheelset center and the spindle center to be approximately aligned on a consistent basis even in cases in which the correct outside diameter of the wheels is unknown.
Errors corresponding to the size of the outside diameter of the wheels arise because of the configuration in which the wheels are raised by two bearing rollers, but correcting the errors allows the wheelset center and the spindle center to be aligned automatically on a consistent basis within an acceptable margin of error.
Although such conventional centering devices can raise and center wheels with good stability by using two bearing rollers, the synchronously lowered centering part must be disposed at the topmost point of the wheels, requiring complex mechanisms and making it difficult to reduce the size and cost of the equipment.
In addition, the centering part and the lifter device must be hoisted synchronously in the manner described above, requiring complex mechanisms to be used and large amounts of time to be spent for positioning and adjusting each part, and bringing about other problems related to practical use.